In the high-volume modified-atmosphere packaging industry, quality and safety concerns demand good and consistent sealing of packages, while profitability concerns demand fast and cost efficient apparatus and packaging methods for products requiring a modified atmosphere. Methods exist which make use of a conveyor apparatus to advance a continuous web of interconnected bags between a pair of opposed belts, insert a product into each bag, draw air out of each bag and inject a gas into the bags, and sever, seal and trim the bags to form product packages containing the product in a sealed, modified atmosphere.
However, existing apparatus and methods have several inefficiencies. For example, known apparatus and methods use an elongate snorkel to draw air out of each bag and inject a relatively inert gas to replace the air. To generally prevent undesired flow of air into a bag or injected gas out of a bag during the air draw-out and gas refill steps, the snorkel has a flattened cross section, enabling it to slide between opposed conveyor belts and into and out of each bag while generally avoiding significant gaps at a mouth of the bag which could allow the undesired gas flow. Consequentially, a design challenge is that the flattened cross-section of the snorkel requires it to have a flat cross-sectional flow area fitting within the circumference, resulting in a slow volumetric draw out and refilling rate for a given flow velocity. On the other hand, increasing the flow velocity risks causing the bag to collapse around the snorkel opening, thus occluding flow.
In addition, providing a web of preformed bags requires using a separate apparatus to form the web of bags, which adds to the total cost of the method, and trimming unsealed edges off of sealed bags requires special trimming equipment and produces waste.
A need therefore exists for faster and more cost-efficient apparatus and methods for modified atmosphere packaging systems.